Q2 acts as an oscillator and the signal coming off C2 is fed onto the base of Q2.L1/C1 is a so called ‘tank’ circuit and operates in the 88-105MHz band on your regular AM/FM radio dial.L1 is a 1uH variable inductor coil to be able to tune it a little bit, and the range of 1uH is approximate.The antenna can be as simple as a 8″ (21cm) piece of wire of any kind.